Code SP0003: DC link fuse blown
Issue Description & Safety Warning
The Fanuc Alpha-i Servo Spindle Amplifier has triggered a critical DC link fuse blown alarm. Immediate attention from a qualified operator or maintenance technician is required to prevent secondary damage to the equipment or spoiled parts during the manufacturing cycle. Always ensure standard safety and LOTO procedures are followed before accessing electrical cabinets.
Official Troubleshooting Steps
Amplifier LED display: 03 Also shown as: SP0003 (15i), SP9003 (30i/31i/32i), SP9003 (0i-D) Cause: The fuse of the DC link has blown. (The voltage at the DC link is insufficient.) This alarm is checked when emergency stop is cancelled. (1) If this alarm is issued during spindle operation (rotation) The fuse of the DC link inside the Spindle Amplifier has probably blown. So, replace the Spindle Amplifier. This alarm may be caused by the following: <1> Power lead short-circuited to ground <2> Motor winding short-circuited to ground <3> IGBT or IPM module failure (2) If the Power Supply input magnetic contactor is once turned on and is turned off with this alarm when emergency stop is cancelled or the CNC is started (When two spindles are connected, the magnetic contactor may not be turned off.) (a) The DC link wire is not connected. Check the DC link wiring for errors. (b) The fuse of the DC link inside the Spindle Amplifier has blown. Replace the Spindle Amplifier.
Source: Fanuc αi Servo/Spindle Amplifier Maintenance Manual (B-65285EN/04) — Part II Troubleshooting
Last reviewed: 2026-07-01 · Verified against the manufacturer’s official documentation.
About Fanuc Alpha-i Servo Spindle Amplifier Alarms
Fanuc controllers include extensive self-diagnostics that flag or halt the machine when a fault is detected. Error code SP0003 on the Alpha-i Servo Spindle Amplifier identifies one specific fault condition — its documented cause and the official corrective steps are listed above, sourced from Fanuc's service documentation. Always confirm against the manual for your exact machine configuration and follow LOTO procedures before servicing.
Complete Alarm List: 135 Fanuc Alpha-i Servo Spindle Amplifier codes.
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